Biofouling
caused by the accumulation of biomolecules on sensing
surfaces is one of the major problems and challenges to realize the
practical application of electrochemical biosensors, and an effective
way to counter this problem is the construction of antifouling biosensors.
Herein, an antifouling electrochemical biosensor was constructed based
on electropolymerized polyaniline (PANI) nanowires and newly designed
peptides for the detection of the COVID-19 N-gene. The inverted Y-shaped
peptides were designed with excellent antifouling properties and two
anchoring branches, and their antifouling performances against proteins
and complex biological media were investigated using different approaches.
Based on the biotin–streptavidin affinity system, biotin-labeled
probes specific to the N-gene (nucleocapsid phosphoprotein) of COVID-19
were immobilized onto the peptide-coated PANI nanowires, forming a
highly sensitive and antifouling electrochemical sensing interface
for the detection of COVID-19 nucleic acid. The antifouling genosensor
demonstrated a wide linear range (10
–14
to 10
–9
M) and an exceptional low detection limit (3.5 fM).
The remarkable performance of the genosensor derives from the high
peak current of PANI, which is chosen as the sensing signal, and the
extraordinary antifouling properties of designed peptides, which guarantee
accurate detection in complex systems. These crucial features represent
essential elements for future rapid and decentralized clinical testing.